Did you like doom2.wad? This is like doom2.wad, only harder. In that respect, D2TWID succeeds quite handily.
That said, I find the maps are good in pretty much inverse proportion to how "experimental" they are, "experimental" being a euphemism for "forget everything the community has learned since 1994 on what makes maps fun to play" or "relive Sandy Petersen's worst ideas". There are many great maps like 3, 6, 11, 13, 15, 18, 23, and 29 that have either fast, fluid combat, rewarding exploration, or both, interspersed with "experimental" maps like 5, 9, 10, 19, 24, and 28 that "experiment" with every possible way to annoy and frustrate the player--mandatory treks across damaging floors sans radsuit, health-tax teleports into crowds of enemies at close range, irritating teleport puzzles, heinous Pain Elemental spam encounters (the entire wad could be treated as a course in how not to use Pain Elementals), awkward platforming, hideous texture combinations. Overall this map has more highs than lows but the lows can get really, really low.
The first time I played this it took me like 10 hours just to complete map 02 because I kept getting stuck and I always try to find as many secrets as I can. In this wad I had pretty bad luck with that. But the journey on your first playthrough is really amazing, you wander around until you finally find the way forward and that always feels really nice. It's cool how the entire map 02 is a mix between exploration and monster fighting. It has its moments that can make you feel uneasy, like spotting random eyes that stare at you through the walls or similiar small details.
The Binding of Isaac secrets are a little silly tho, to be honest. I do love the replacement for the BFG tho! Balancing your health for a burst of damage is a fun and risky mechanic.
Map 03 is way more straightforward, it's like a short gauntlet towards the final boss. This map has a lot of parts that can feel unfair, like spawning explosive Lost Souls or trap bombs right next to you. Or the abundance of Archviles later on. While I personally don't mind the Archvile library, it can still royally mess you up if you don't take them step by step.
The final boss could be fun too, but its 2nd phase is just too much. More strong monsters and also Archviles, with zero walls to hide behind. I have never been able to beat the final boss legit, I always get one of the randomized powerups and hope I get an invulnerability, so I can spam the Necronomicon endlessly. It's the only way I can beat it, the fight is either way too hard or way too easy if you use this method.
I love the ending tho, very creepy.
This might just be my favourite horror-ish Doom wad of all time, apart from myhouse, Maskim Xul and maybe some other ones.
What I like:
+the overall theme
+your house being a hub area
+the dark atmosphere
+the semi open-endedness of the progression
+there are no jumpscares or anything of that sort
+the fact that the game remembers your progress while alternating between maps
+the difficulty, even tho it is indeed a little too much sometimes
What I dislike:
-A few certain fights that feel unfair (some examples: the long hallway where you get one of the keys and Archviles spawn behind you, there's no place to hide from their attack; or later when you return to the lower floors of the 1st major area, the fights in the narrow rooms with Archviles, immediately followed by a swarm of chainsaw zombies, where your only hope is to camp on top of an object; or some of the slaughter fights later on, especially in the chapel area)
-the ending feels meh